The Washington Nationals have signed 24 year old right-handed pitcher Caleb Clay to a minor league deal. Clay was a sandwich pick (44th overall but technically 1st round) in 2006 by the Red Sox and has spent his entire career there. After pitching mostly as a starter through 2010, he was moved to the bullpen when he moved up to AA. He had Tommy John Surgery in 2007, but the move to the bullpen probably had more to do with mediocre results in 2011 and 2012, as he had a 4.40 FIP in Class A (3.70 League Average ERA) and 3.96 FIP (3.90 League Average ERA) in Advanced A. The move to the bullpen didn't seem to help, as over the last two years he has thrown 122.1 AA innings with a FIP 1.04 over league average and SIERA .05 better than league average. So obviously the problem Clay has been having is home runs (1.54 HR/9IP), which probably has to do a lot with his ground-ball rate (33.9 %). He has not exactly pitched in a pitcher friendly environment with a 107 Park Factor over the last two years, and a move to the Nationals organization will help, as both their AA and AAA parks were harder to hit homers in this year than their respective league averages (with AA Harrisburg playing below league average overall and AAA Syracuse playing roughly league average overall). As you would expect, Clay was better on the road in his two years in AA, but his HR/9IP was actually higher on the road. It was his K/BB that was better on the road, which is rather weird (though 63 road innings versus 59.1 innings at home are not large sample sizes).
Clay pitched in a short sample in the Arizona Fall League in 2011 so we have Pitch F/X data from one of his outings. His fastball was about average, at 91.57 MPH. He also threw a hard slider at 87 MPH, a curve at 72 MPH, and a changeup at 83 MPH. According to other scouting reports, his fastball is below average at 88-90 MPH (at one time his fastball got up to 95 MPH according to Baseball America and Sox Prospects) and the slider is not as hard as Pitch F/X picked it up. The changeup is evidently his best pitch for whiffs and he has good control, which shows up statistically as well, as even though he struggled with walks in 2011, he walked just 6.5% of batters in 2012. Baseball America said he had the best in the Carolina League in 2010 (he walked just 4.8 % of batters that year).
In watching video of him, his delivery is pretty standard other than it seems he brings his leg out towards 3rd base and up a little more than usual. To me, his best pitch is his slider, which sweeps from left to right in a very hard fashion, though I can see why some like his changeup. However, this MLB Prospect Portal video is probably a good summation of his career so far:
He threw some good breaking balls down and kept the ball low with good control, but even though he had the platoon advantage (he hasn't really had major platoon splits over the last two seasons), a ball out of the strike zone was driven out of the ballpark. It doesn't seem like their is anything wrong with his pitchability, it just looks like his stuff isn't good enough.